the reason for lack of integration is that its a holdover from when NYC's subways were essentially run by two competing companies and the path was unofficially the third subway company in the region. Because of this weird competition, the path never integrated with the other systems and has been treated like the step child.

There is alot of holdover from that time too, like a planned extension of the path to Grand Central that was abandoned because the company that ran the east side subway system bought the underground land rights up to like 100 feet in order to prevent the path from building as the deeper the tunneling the more expensive it would be, etc.

While I dont think the Path should be run by MTA, I do think there needs to be a standard fare that is transferable to all the systems in the area. Does not make sense to have like 6 different transit systems and all have their own fares and price points for monthly plans